The invention relates to a floating, nonsubmersible nautical craft in particular for the observation, dry, and in constant communication with the atmosphere of the underwater medium.
We are already familiar with many nautical craft, particularly for underwater observation.
In a known variation, the craft has a generally vertical axis of symmetry, and includes an upper buoyancy platform and a vertical well associated with the center of the platform by its upper part, having observation portholes. The well either occupies a position which is fixed relative to the platform or is movable slidably along the axis of symmetry. This known variation has a very large number of drawbacks. The design and shape of the craft (platform and well) make is unsuitable for easy travel, and do not provide satisfactory stability. The draft of the vessel is substantial, and it cannot be used in shallow depths. This draft is invariable or slightly variable. The craft is intended to accommodate a single passenger or a very limited number of passengers.
The sturdiness of the craft, owing to its structure, is dubious. The entry and exit of the passengers to and from the cabin by a steep inside ladder is perilous, this ladder either having to be moved, or will interfere with observation. Thus such a craft is entirely unsuitable for observation of the underwater medium by its passengers under conditions of great comfort and safety.
In another known variation, the craft appears in the general form of a conventional boat hull having a central opening and a cabin with a porthole, pivotally associated with the hull, mounted in the opening between a lower, observation, position and an upper, retracted, position. The cabin can be provided with ballast units, which are likewise movable. This variation also has numerous drawbacks. The association of the cabin with the hull is not very reliable; the displacement of the cabin, in rotation, makes continuous access for entry to or departure therefrom impossible, the stability of the craft is dubious; the craft will not accommodate a large number of passengers, nor can it vary the draft when passengers are in the cabin.
In another known variation, the craft has a pontoon to accommodate passengers, associated with immersed elements, rigidly associated with the pontoon and placed on either side of it. But such a craft by its very nature does not permit underwater observation.
In another known variation, the craft has a vertical axis of symmetry and includes a platform of circular contour under which an immersed observation chamber of toric shape is attached. But this installation is stationary, forming merely an underwater observation gallery and in no case a mobile craft that can travel from a site of embarkation and debarkation to various observation sites. In another known variation, the craft is a conventional vessel, in which the immersed part of the hull has observation portholes. But such a craft remains largely theoretical because its embodiment encounters numerous difficulties; obtention of sufficient draft, solidity, safety.
In another known variation, the craft is a conventional boat with transparent bottom. But such a craft is not designed specifically for observation of the underwater medium; vision is essentially vertical and limited in quality; the observation remains properly speaking, outside the underwater medium.
In another known variation, the craft is a submarine designed to be fully immersed, which involves sophisticated details of tightness, ventilation and safety, and prevents continuous communication with the outer air.